Yeah, a flush might be a good idea. Generally 2X the amount of the size of the pot is good.. Example 5 gallon pot flush with 10 gallons of water. Should be alright after just a flush, let her dry out real good and back off the nutes a little.
Steel, to me looks like they are lacking a little bit of nitrogen, but while flowering that is normal for foliage to start yellowing a bit, due to lower N and higher PK values...
Is that stuff happening on lower parts of the plant that are really shaded? I've noticed on my girls that the stuff I dont trim off that's really shaded dies off any way.
In any posting by that person , there should be the old school scales on the top right of the post, they are silver I believe. If you click them it will say leave a message or something like that, type it in and hit approve